SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8fe0786a2cf4fc0f3fb4326baca29ba163378ae9705bdd2c1e190676016586da' 
  AND token = '8sls0p7+LUGz/4WCqai9+jII+RHbBeHJMd5KLsc7qG4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}